1. Field of the Invention
The present invention is related to an information processing apparatus, an information processing method, and a computer-readable encoding medium recorded with a computer program thereof.
2. Description of the Related Art
Recently, wavelet transformation has been increasingly used for image compression/depression as a frequency transformation taking the place of a DCT (Discrete Cosine Transform). A typical example of the wavelet transformation is an image compression/decompression method of JPEG 2000 which is now the successor of JPEG and became the international standard in 2001.
Codes (hereinafter, also called JPEG 2000 code) encoded by a JPEG 2000 method can be accessed by packet units or simpler tile part units. This means that it is possible to extract necessary codes from original codes and generate new codes. Also, this means that it is possible to decode codes alone partially acquired from the original codes if necessary.
For example, in a case of displaying a large image residing in a server at a side of a client, it is possible to receive and decode codes for a desired resolution only, codes for a desired portion only to view, or codes for a desired component only to view, from the server.
As described above, a protocol for receiving necessary codes from JPEG 2000 codes residing in the server is called JPIP (JPEG 2000 Interactive Protocol). The protocol for partially accessing a hierarchical image can be seen in a FlashPix™ which depicts an image in a multi-resolution and in an IIP (Internet Imaging Protocol) which is a protocol to access the FlashPix™.
For example, Japanese Laid-open Patent Application No. 11-205786 discloses a technology that enables selecting to indicate at least one of a resolution, a display range, and a frame rate and downloading an image corresponding to one frame of a motion picture by a unit of the pixel group element piece, from a server storing an image.
Also, Japanese Laid-open Patent Application No. 2003-23630 discloses a technology relating to a cache model and a like in the JPIP.
In a case of using the above-described JPIP, it is suggested to instruct a resolution desired to draw an image and a window size to actually draw on a screen, from a client to a server. When the server receives this instruction from the client, the server sends a packet of a precinct sufficient to conduct a frequency inverse transformation for an area of the instructed resolution, or further simply sends codes of tiles (or tile parts) covering the area.
The wavelet coefficient has a correspondence with a location of an original image, and the precinct indicates a position. In a case of inversely transforming the wavelet coefficient, a coefficient inside the precinct and a coefficient outside the precinct are not independent of each other, and an accurate wavelet inverse transformation cannot be conducted by using only the coefficient inside the precinct.
Accordingly, in a case of inversely transforming the wavelet coefficient inside the precinct received at a side of the client, there is a case in which the coefficient outside the received precinct is also required. Thus, there is a case in which a wavelet inverse transformation cannot be adequately conducted by using the received precinct only.